One of functions of a car navigation device mounted on a vehicle is a traffic information notification function. When a traffic hazard such as traffic congestion occurs in a route to a destination, the car navigation device having the traffic information notification function notifies the traffic hazard to a user (driver) to guide the route to the destination. However, when a destination is not set, even if an occurrence of a traffic hazard is detected, whether or not an own car passes an occurrence position of this traffic hazard is typically unknown. Therefore, car navigation devices do not generally notify the traffic hazard.
Meanwhile, following Patent Documents 1 and 2 disclose car navigation devices which, when a destination is not set, estimate a traveling route of an own car and notifies information about a traffic hazard which the car is likely to encounter, to users.